The Physics of the Tooth Fairy

When I was very little, I wanted to find the physics of the tooth fairy. I didn’t know that’s what it was called, or that this is how science actually works; this knowledge only came to me much later, after years of learning myths about physics and then more years of replacing these myths by truths about what would eventually become the main interest in my life.

But when I was very little, all I knew was that the tooth fairy operated like clockwork, with a clear method. It started with one of my teeth getting loose in my mouth, and ended with a surprise present under my pillow. I decided I should figure her out, the tooth fairy, and her method. If I could only anticipate where she will be, and when, maybe I can get more presents, I reasoned to my soon-to-be toothless self.

For three fallen teeth I made observations, making little squiggly notes that only I could understand. I measured how much time it took from the moment a tooth started becoming loose to the moment my parents reported the tooth fairy is waiting for it (about two days). I counted the days it took for the tooth to actually fall (about a week). I measured the average time it took for the present to appear on my pillow (about a day).

Then I started experimenting. I announced to my parents that a tooth is wiggly even when it wasn’t, testing the fairy’s false-positive response. She knew better. I hid a fallen tooth in the highest shelf of my closet. The tooth fairy didn’t take my tooth that day, but I still got a gift. I concluded she was very short.

But when presents were concerned, nothing seemed to faze the fairy. She kept delivering the presents accurately, exactly one evening after I put each tooth under my pillow, like clockwork. Only once did the fairy changed ways; it was a rainy night, and I was sick with the flu. My mother handed me the fairy’s gift in exchange for my tooth. Tooth fairy was stuck in the storm, and apologized, promising to bring me something bigger on the next tooth. I concluded the fairy really needs to get a fairy-car.

When I ran out of baby-teeth, I had no more choice but to go with what I had.

I summarized everything and reached the conclusion.

It was the first scientific experiment I have devised.

It was the best gift the tooth fairy gave me.